The present invention relates generally to inkjet printable media. More particularly, the present invention relates to security documents such as passports.
There are numerous security documents which comprise a paper substrate. Examples of security documents comprising a paper substrate include, certificates (e.g., stock certificates), negotiable instruments (e.g., checks), passports, and visas. A passport typically includes one or more sheets of paper. Often, a photograph of the person to whom the passport is issued is placed onto the paper and laminated in place using a transparent polymer film. One of the shortcomings of this construction is that the photograph is raised from the page and may be carefully removed by a skilled counterfeiter and replaced with a different photograph.
A common complaint made by passport holders is that the photograph is often not a flattering portrait. This complaint is so widespread that writers and performers who specialize in humor have addressed this subject. For example, one book of humorous stories was titled, xe2x80x9cWhen You Look Like Your Passport Picture it""s Time to Come Homexe2x80x9d. Fortunately for travelers, digital camera technology has become increasingly wide-spread and economical in recent years. For example, many portrait studios now use digital cameras.
When a portrait is taken with a digital camera, the cost of taking multiple shots is very low. The low cost allows several images to be taken. These images can all be viewed immediately on a computer screen, and the subject may choose the ones he or she likes best. The unflattering images can be discarded, and the desirable images can be saved electronically. A hard copy of the desirable images can also be created using a printer, for example, an inkjet printer.
In recent years, the price of inkjet printers has come down dramatically. At the same time, the quality of the images produced by inkjet printers has dramatically improved. Today, an inkjet printer capable of producing near photographic quality images can be purchased at any large electronics retailer.
The present invention relates generally to inkjet image retaining assembly. More particularly, the present invention relates to security documents such as passports. The invention is directed to a class of ink-receptive translucent coating materials which may be applied to paper based documents including security papers to provide a robust, durable, high quality, and tamper resistant image after processing.
Ink receptive media in accordance with the present invention comprise a substrate, and an ink receptive layer comprising a plurality of particles. In a particularly preferred embodiment, the ink receptive layer comprises a plurality of crosslinked poly(vinylpyrrolidone) particles. In a useful embodiment of the present invention, the particles of the ink receptive layer define interstitial spaces. In a preferred embodiment of the present invention, the particles of the ink receptive layer define a plurality of tortuous paths extending between a first major surface and a second major surface of the ink receptive layer. It is believed that the plurality of tortuous paths may allow a fluid vehicle of the ink composition to pass through the ink receptive layer to be carried away by the substrate. In a particularly preferred embodiment, the ink receptive layer is capable of capturing most of the ink colorants near a first major surface of the ink receptive layer while allowing most of a fluid vehicle of the ink to pass through the ink receptive layer and to be carried away by the substrate.
In one embodiment of the present invention, a laminate is heat sealed over the first major surface of the ink receptive layer. In a preferred embodiment, the ink receptive layer has a thickness of between about 2 microns to about 100 microns dry. In a more preferred embodiment, the ink receptive layer has a thickness of between about 5 microns to about 50 microns dry. It is believed an ink receptive layer in accordance with these preferred embodiments may allow material from the laminate to flow through the ink receptive layer and bond to the substrate.
Ink receptive compositions in accordance with the present invention are useful to modify paper to render it printable to obtain an acceptable image with aqueous inks, particularly from an inkjet printer. Images printed on paper to which the ink receptor composition has been applied are of excellent image quality compared to printed images on paper without the ink receptor composition. The ink receptor composition of this invention is especially useful for security documents and other applications where a heat sealable laminate is to be adhered to the imaged article.
One embodiment of a multi-layered structure in accordance with the present invention includes a substrate and an ink receptive layer comprising one or more projections overlaying a top surface of the substrate. The multi-layered structure also includes a laminate having a top layer and a bottom layer. The material of the bottom layer of the laminate preferably extends between the projections of the ink receptive layer and contacts the top surface of the substrate.